Luminosity and Light Source Distance
Mathematician(s): _______________________________________________________
Luminosity and Light Source Distance
For this experiment, you need to test the luminosity of a LED or RGB LED from varying distances—predict what you think will happen to the luminosity readings as the distance between the light source and the sensor increases? Will the luminosity increase, decrease or stay the same as the distance increases?). Tape your working LED circuit to the left edge of the paper (you may want to tape your paper to the table as well so nothing shifts during your experiment. Record your luminosity readings at each distance mark. Repeat this experiment 3 times and then follow the directions on the back of the paper to analyze your data.
Distance:
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Distance: Distance from the
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Lux
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Lux
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Average Luminosity
(Unit: _______)
(Unit: ______)
Average:
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Mathematician(s): _______________________________________________________
Now, let’s take some time to organize our data into a graph and see if we can predict the relationship between the distance from the sensor and the average luminosity. First, you need to decide which value (distance or luminosity) is the dependent variable and which value is the independent variable. The dependent variable is affected by the other variable—the dependent variable depends on the
independent variable. The independent variable isn’t affected by the other variable—the independent variable does not depend on the dependent variable. The independent variable is typically represented by the x-axis or the input, the dependent variable is typically represented by the y-axis or the output. Title: ________________________________________________________________
Label your axes and graph the data you collected in the experiment above. Reflection. 1.
Based on your data, what do you think the luminosity reading at 8 inches away from the
Dependent Variable (Units): ___________________________
sensor will be? Why?
How can you determine the luminosity reading at 12 inches away?
How can you determine the luminosity reading at 20 inches away?
At what distance will the luminosity reach approximately 50 lux?
At what distance will the luminosity reach 0 lux?
2.
Write a sentence that describes the luminosity reading at any distance away from the sensor.
3.
Write your sentence from #2 in the form of an equation using only numbers and symbols and test your equation to see if it generates the values in your table.
Independent Variable (Units): ___________________________________
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Mathematician(s): _______________________________________________________
Shown below on the left are common function families. Can you match your data to one of the function families? 4.
Which function closely replicates your data? Explain your reasoning. Check your data in the equation and use it to justify your choice.
http://calcwithtully.weebly.com/parent-functions.html
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